Assessment of Efficiency of Bioactive Glass, Self-Assembling Peptide, and Ozone Remineralising Agents on Artificial Carious Lesion

ABSTRACT Objective: To assess the efficacy of bioactive glass, self-assembling peptide, and ozone-remineralizing agents on the artificial carious lesion. Material and Methods: On the extracted 60 premolar teeth, an artificial carious lesion/demineralization was created. Later, the remineralization of demineralized teeth was done with respective remineralizing agents (Group A: Calcium sodium phosphosilicate (bioactive glass), Group B: Self-assembling peptide, Group C: Ozone remineralizing agents and Group D (Control): De ionized water. The degree of demineralization and remineralization were evaluated using the Vickers Hardness Number. Results: There was a decrease in microhardness from baseline to demineralization in all the groups, and this reduction was found to be statistically considerable. After the remineralization of demineralized samples with respective remineralizing agents, there was an increase in microhardness of 312.38, 276.67, and 254.42 in groups A, B, and C, respectively. In contrast, in Group D, there were no changes. Conclusion: Bioactive glass and self-assembling peptides had higher remineralizing capacities, which can be used to treat early carious lesions.

Three-dimensional non-destructive visualization of teeth enamel microcracks using X-ray micro-computed tomography.

Although the topic of tooth fractures has been extensively analyzed in the dental literature, there is still insufficient information about the potential effect of enamel microcracks (EMCs) on the underlying tooth structures. For a precise examination of the extent of the damage to the tooth structure in the area of EMCs, it is necessary to carry out their volumetric [(three-dimensional (3D)] evaluation. The aim of this study was to validate an X-ray micro-computed tomography ([Formula: see text]CT) as a technique suitable for 3D non-destructive visualization and qualitative analysis of teeth EMCs of different severity. Extracted human maxillary premolars were examined using a [Formula: see text]CT instrument ZEISS Xradia 520 Versa. In order to separate crack, dentin, and enamel volumes a Deep Learning (DL) algorithm, part of the Dragonfly's segmentation toolkit, was utilized. For segmentation needs we implemented Dragonfly's pre-built UNet neural network. The scanning technique which was used made it possible to recognize and detect not only EMCs that are visible on the outer surface but also those that are buried deep inside the tooth. The 3D visualization, combined with DL assisted segmentation, enabled the evaluation of the dynamics of an EMC and precise examination of its position with respect to the dentin-enamel junction.

Evaluación de la resistencia a la fractura de dientes instrumentados con Protaper Gold, Protaper Next y Waveone Gold / Evaluation of the fracture strength of teeth instrumented with protaper gold, protaper next and waveone gold

INTRODUCCIÓN: el tratamiento de conductos produce cambios físico-químicos en la dentina y una pérdida estructural significativa para el diente, lo que lo hace más susceptible a la fractura. MATERIAL Y MÉTODOS: 64 premolares mandibulares fueron decoronados y divididos aleatoriamente en cuatro grupos (n = 16): grupo control (CG) no tratado, grupo instrumentado ProTaperGold® (PTG®) (25.08), grupo instrumentado ProTaperNext® (PTN®) (25.06) y grupo instrumentado WaveOne Gold PRIMARY® (WOG®) (25.07). Durante la instrumentación, se realizó la irrigación con NaOCl al 5,25% con una jeringa Monoject® y tras la instrumentación, las muestras se irrigaron con NaOCl, EDTA 17% y NaOCl activado sónicamente. Los conductos radiculares se obturaron utilizando el sistema B&L®, y posteriormente se colocaron en bloques de resina acrílica estandarizados para ser cargados con una fuerza vertical constan-te de 0,02 mm/s hasta que se produjo la fractura de la raíz, mediante una máquina de ensayo universal (ME-405/20, Servo-sis®). Las comparaciones entre grupos se analizaron con la prueba ANOVA.RESULTADOS: No hubo diferencias esta-dísticamente significativas (p > 0,05) entre el GC y los grupos instrumentados con PTN® y WOG®; tampoco entre los grupos PTN® y WOG®. Sin embargo, se obtuvieron diferencias estadísticamente significativas entre el grupo instrumentado con PTG® y el resto de los grupos, siendo el grupo PTG® el más susceptible a la frac-tura. CONCLUSIONES: El sistema PTG® fue el que más debilitó las raíces después de la instrumentación, en comparación con los sistemas WOG® y PTN®

INTRODUCTION: root canal treatment produces physicist-chemist changes in the dentine and a significant structural loss for the tooth what makes it more susceptible to fracture. MATERIAL AND METHODS: 64 mandibular premolar were decoronated and randomly divided into four groups (n = 16): control group (CG) non-treated, ProTaper Gold(TM) (PTG(TM)) instrumented group (25.08), ProTaper Next(TM) (PTN(TM)) instrumented group (25.06) and WaveOne Gold(TM) PRIMARY (WOG(TM)) instrumented group (25.07). While shaping, cleaning was done with NaOCl 5,25% using a Monoject(TM) syringe and after shaping, roots were irrigated with NaOCl, EDTA 17% and NaOCl sonically activated. Root canals were obturated using B&L(TM) system, embedded into standardized acrylic resin blocks and load with a constant vertical force of 0,02 mm/s until root fracture was produced using a universal testing machine (ME-405/20, Servosis(TM)). Comparisons among groups were analyzed with ANOVA test. RESULTS: There were no statistically significant differences (p > 0.05) between the CG and the groups instrumented with PTN(TM) and WOG(TM); neither among PTN(TM) and WOG(TM) groups. However, statistically significant differences were obtained between the group instrumented with PTG(TM) and the rest of the groups being PTG(TM) group the most susceptible to fracture. CONCLUSIONS: PTG(TM) system was the one that weakened more the roots after the instrumentation in comparison with the WOG(TM) and PTN(TM) systems

The influence of restorative material and glass fiber posts on fracture strength of endodontically treated premolars after extensive structure loss.

OBJECTIVE: The aim of this in vitro study was to investigate the fracture strength and cuspal deflection of endodontically treated premolars restored using different composite resins along with or without fiber post application. MATERIALS AND METHOD: Eighty intact premolars were randomly divided into eight groups (n = 10); CO group: intact teeth (control), OPR group: mesio-occlusal-distal-palatal (MODP) preparation (OPR) + endodontic treatment (ET), TC group: MODP preparation + ET + Tetric N-Ceram, TB group: MODP preparation + ET + Tetric EvoCeram Bulk Fill, SO group: MODP preparation + ET + SonicFill 2, TC-P group: MODP preparation + ET + Hahnenkratt glass fiber post + Tetric N-Ceram, TB-P group: MODP preparation + ET + Hahnenkratt glass fiber + Tetric EvoCeram Bulk Fill, and SO-P Group: MODP preparation + ET + Hahnenkratt glass fiber post + SonicFill 2. After thermocycling, specimens were subjected to a compressive load until fracture. Data were analyzed using analysis of variance and Tukey tests (P < 0.05). RESULTS: The mean fracture strength of groups which received post treatment showed similar fracture strength values [TC-P (931.6 ± 97.9), TB-P (882.0 ± 59.7), SO-P (862.0 ± 143.0) (P > 0.05)] and was significantly higher than OPR (530.6 ± 41.7), TC (841.2 ± 93.1), TB (774.5 ± 101.8), and SO (735.0 ± 178.01) groups (P < 0.05). No significant difference was detected among groups considering cuspal deflection (P > 0.05). The fiber post insertion resulted in more unfavorable fractures. CONCLUSION: Endodontically treated teeth restored with fiber post and bulk-fill or conventional composite resins demonstrated fracture strength values similar to intact teeth.

Vertical Root Fracture in Buccal Roots of Bifurcated Maxillary Premolars from Condensation of Gutta-percha.

INTRODUCTION: Maxillary premolars are among the teeth most susceptible to vertical root fracture (VRF) from lateral condensation of gutta-percha. These teeth are distinguished by a complex anatomy of the buccal root including a large depression in the dentin wall facing the bifurcation. It is hypothesized that tooth sectioning coupled with 2-dimensional fracture analysis is instrumental in understanding VRF in such teeth. VRF was examined by tooth sectioning following the development of a fracture mechanics analysis to predict VRF in such roots. METHODS: The fracture morphology in teeth extracted from patients because of VRFs was examined from a series of horizontal cross sections. 2-dimensional fracture mechanics analysis in conjunction with the finite element technique was developed to evaluate VRF caused by canal pressure (q). As in our previous single-rooted tooth model, the apical obturation force (F) was related to q using a simple formula. RESULTS: Fracture was mostly limited to the buccal root, exhibiting some competing modes including fracture from the depression peak to the canal surface and the canal surface to the root surface, which may occur either along straight lines or curved trajectories resembling the depression outline. The analysis predicted clinical fractures well, yielding VRF force values in the upper range used by clinicians during lateral condensation of gutta-percha. CONCLUSIONS: The main etiology for VRF is stress concentration resulting from the combined effect of wedgelike canal depression and the flexibility of periodontal ligament tissue joining the root and bone. This drawback can be alleviated by minimizing canal enlargement and apical condensation force during root canal therapy.

Duration from Initial Symptoms to Diagnosis of Vertical Root Fracture in Dental Offices.

Diagnosing vertical root fracture (VRF) is difficult. Here, we retrospectively investigated the duration from initial symptoms to a definite diagnosis of VRF in dental offices. Data were collected on patients with VRF between July 2013 and June 2015. Initial symptoms were ascertained from clinical records. The focus was on the maxillary second premolars and mesial roots of the mandibular first molars, where VRF is most frequent. All VRF in the bilateral dentition was analyzed. Only cases in which the buccal-lingual plane of the root was fractured were included. Data from 31 dental offices revealed a total of 39 VRFs in the maxillary second premolars and 43 in the mandibular mesial roots of the first molars. The patients comprised 42 males and 40 females, and the average age was 59.7±11.6 years at initial onset of symptoms. The mean duration from initial symptoms to a definite diagnosis in the maxillary second premolars was 18.3±22.5 months, while that in the mandibular first molars was 16.1±17.8 months. The cumulative diagnostic rate was 48.7% at 12 months and 79.5% at 24 months in the maxillary second premolars, and 38.1% at 12 months and 86.0% at 24 months in the mandibular first molars. No significant difference was observed between tooth type. If VRF is suspected, doctors should explain the risks of tooth extraction and begin considering treatment options. The present results revealed that 80% of VRFs were diagnosed within 2 years of initial onset of symptoms.

Effect of bulk-fill base material on fracture strength of root-filled teeth restored with laminate resin composite restorations.

OBJECTIVES: To evaluate the effect of using a bulk-fill flowable base material on fracture strength and fracture patterns of root-filled maxillary premolars with MOD preparations restored with laminate restorations. METHODS: Fifty extracted maxillary premolars were selected for the study. Standardized MOD cavities with endodontic treatment were prepared for all teeth, except for intact control. The teeth were divided randomly into five groups (n=10); (Group 1) sound teeth, (Group 2) unrestored teeth; (Group 3) MOD cavities with Vitrebond base and resin-based composite (Ceram. X One Universal); (Group 4) MOD cavities with 2mm GIC base (Fuji IX GP) and resin-based composite (Ceram. X One Universal) open laminate, (Group 5) MOD cavities were restored with 4mm of bulk-fill flowable base material (SDR) and resin-based composite (Ceram. X One Universal). All teeth were thermocycled and subjected to a 45° ramped oblique load in a universal testing machine. Fracture load and fracture patterns were recorded. Data were analyzed using one-way ANOVA and Dunnett's T3 test. RESULTS: Restoration in general increased the fracture strength compared to unrestored teeth. The fracture strength of group 5 (bulk-fill) was significantly higher than the fracture strength of the GIC laminate groups and not significantly different from the intact teeth (355±112N, P=0.118). The type of failure was unfavorable for most of the groups, with the majority being mixed failures. CONCLUSIONS: The use of a bulk-fill flowable base material significantly increased the fracture strength of extracted root-filled teeth with MOD cavities; however it did not improve fracture patterns to more favorable ones. CLINICAL SIGNIFICANCE: Investigating restorative techniques that may improve the longevity of root-filled premolar teeth restored with direct resin restorations.

Replacing Heavily Damaged Teeth by Third Molar Autotransplantation With the Use of Cone-Beam Computed Tomography and Rapid Prototyping.

This article describes the autotransplantation of third molars to replace heavily damaged premolars and molars. Specifically, this article reports on the use of preoperative cone-beam computed tomographic planning and 3-dimensional (3D) printed replicas of donor teeth to prepare artificial tooth sockets. In the present case, an 18-year-old patient underwent autotransplantation of 3 third molars to replace 1 premolar and 2 molars that were heavily damaged after trauma. Approximately 1 year after the traumatic incident, autotransplantation with the help of 3D planning and rapid prototyping was performed. The right maxillary third molar replaced the right maxillary first premolar. The 2 mandibular wisdom teeth replaced the left mandibular first and second molars. During the surgical procedure, artificial tooth sockets were prepared with the help of 3D printed donor tooth copies to prevent iatrogenic damage to the actual donor teeth. These replicas of the donor teeth were designed based on the preoperative cone-beam computed tomogram and manufactured with the help of 3D printing techniques. The use of a replica of the donor tooth resulted in a predictable and straightforward procedure, with extra-alveolar times shorter than 2 minutes for all transplantations. The transplanted teeth were placed in infraocclusion and fixed with a suture splint. Postoperative follow-up showed physiologic integration of the transplanted teeth and a successful outcome for all transplants. In conclusion, this technique facilitates a straightforward and predictable procedure for autotransplantation of third molars. The use of printed analogues of the donor teeth decreases the risk of iatrogenic damage and the extra-alveolar time of the transplanted tooth is minimized. This facilitates a successful outcome.

Evaluation of Root Fracture in endodontically treated Teeth using Cone Beam Computed Tomography.

AIM: Our objective was to perform an in vitro evaluation of root fracture in endodontically treated teeth using two cone beam computed tomography (CBCT) machines. MATERIALS AND METHODS: The sample comprised 86 single-rooted human premolars that had been fractured by a universal testing machine. The tomographic images were acquired using an Orthopantomograph OP300® and an Orthophos XG 3D® and evaluated by three examiners, by means of specific software. The teeth were classified into presence or absence of root fracture, then the root third where the fracture occurred, was determined. With regard to the detection of the fracture, the Kappa statistic was used for intra and interexaminer repro-ducibility at two distinct points in time. Chi-squared test was employed to analyze the sensitivity and specificity of the two tomographs (p < 0.05). RESULTS: The results showed a good or excellent Kappa index between examiners. As for the absolute frequency, the sensitivity (0.6) of the Orthophos XG 3D® equipment was superior, while specificity (0.91) was higher with the Orthopantomograph OP300®. On the receiver operating characteristics curve, moderate performance was found with an accuracy of 0.73 (OrthopantomographOP300®) and 0.74 (Orthophos XG 3D®) respectively. As far as the location of the root fracture is concerned, moderate agreement was verified using the Kappa statistic (k = 0.56). CONCLUSION: Although the regular CBCTs represent the imaging examination of choice for assisting root fracture diagnosis in endodontically treated teeth, their performance in this study demonstrated an imprecise diagnosis of fractures in a good many cases, irrespective of the tomography machine used. CLINICAL SIGNIFICANCE: An early and precise detection of root fractures is of the utmost clinical importance, but the radiopaque and/or metallic filling materials in the CBCT viewing field may generate artifacts, known as the beam-hardening effect, which could compromise root fracture detection.

[Impact of apical preparation diameter on fracture resistance of mandibular premolar roots].

OBJECTIVE: To compare the fracture resistance of roots of mandibular premolar with different apical preparation diameters. METHODS: Sixty single-rooted single canal permanent mandibular premolar teeth extracted newly for orthodontic reason without immatureness, fracture or cracks were selected, with a curvature less than 10°, and internal length: short diameter of less than 2 at a level 5 mm from the apex. All the teeth were decoronated, leaving roots 13 mm in length. The initial apical file size for the teeth was ≤15#. The roots were assigned to 6 groups based on weights with random block design. Group A: blank control group, no instrumentation was performed. Groups B-F: the master apical file (MAF) was 40#, 45#, 50#, 55# and 60#, respectively. In the five experimental groups the roots were instrumented using hand files with step-back technique at 1 mm increments, resulting in a taper of 0.05. The irrigant used was distilled water. After mounted in acrylic resin, all the teeth were subject to vertical loading using an Instron testing machine until fractured. The occurrence of fractures was detected when the applied load suddenly decreased. The fracture load values and fracture modes were recorded. One-way ANOVA and post-hoc Tukey test were used to determine the difference of fracture load values between the groups (P<0.05). Chi-square tests were used to compare the modes of root fracture. RESULTS: Five experimental groups exhibited lower fracture load values than that of control group [(1 444±155) N]. The mean fracture load values for roots instrumented to an apical diameter of 50# [(1 027±128) N], 55# [(994±150) N] and 60# [(983±166) N] were significantly lower than that of control group and 40# group [(1 339±131) N] and 45# [(1 287±144) N] (P<0.05). Buccal-lingual fracture, mesio-distal fracture and compound fracture occurred 55%, 13% and 32%, respectively. No difference of fracture mode was detected in the six groups. CONCLUSION: The fracture resistance reduced significantly when the roots were instrumented to an apical diameter of 50# or larger.

Vertical root fractures of endodontically treated posterior teeth: A histologic analysis with clinical and radiographic correlates.

Vertical root fractures (VRFs) usually develop slowly, unnoticed by the patient until clinical signs and symptoms become apparent. In endodontically treated teeth, a VRF is a typical cause for extraction. The objective of the present study was the histologic analysis of VRFs in extracted, endodontically treated premolars and molars. In addition, clinical and radiographic findings of these VRF-affected teeth were retrospectively evaluated. Thirty extracted teeth with a clinically diagnosed VRF were embedded in methylmethacrylate. Serial ground sections (perpendicular to the longitudinal axis of the root) were stained with toluidine blue and basic fuchsin. The specimens were photographed and assessed with regard to the vertical and horizontal extent as well as to the course of the VRF. Most VRFs ran from the cervical to the apical region (81.3%). In the axial plane, 50% of VRFs traversed the root completely from buccal to oral. Another 40.6% of VRFs were limited to the buccal root portion. 84.4% of the evaluated roots presented an isthmus. Overall, the VRF was associated with the isthmus in 56.3%, but bypassed the isthmus in 28.1%. The most frequently observed clinical findings included pain (in 60% of the evaluated cases), presence of a fistula (46.7%) and an isolated periodontal pocket with ≥6 mm probing depth (40%). A periapical radiolucency (53.3%) was the most frequent radiographic finding in VRFs. “J-shape” lesions were seen in eight cases (26.7%).

Incidence of microcracks in maxillary first premolars after instrumentation with three different mechanized file systems: a comparative ex vivo study.

OBJECTIVES: The objective of this study is to determine the potential for microcracks in the radicular dentin of first maxillary premolars using three different mechanized endodontic instrumentation systems. METHODS: Eighty extracted maxillary first premolars with two root canals and no externally visible microcracks were selected. Root canal instrumentation was performed with either the ProTaper file system, the WaveOne primary file, or the self-adjusting file (SAF). Teeth with intact roots served as controls. The roots were cut into segments and examined with an intensive, small-diameter light source that was applied diagonally to the entire periphery of the root slice under ×20 magnification; the presence of microcracks and fractures was recorded. Pearson's chi-square method was used for statistical analysis, and significance was set at p < 0.05. RESULTS: Microcracks were present in 30 and 20 % of roots treated with the ProTaper and WaveOne systems, respectively, while no microcracks were present in the roots treated with the SAF (p = 0.008 and p = 0.035, respectively). Intact teeth presented with cracks in 5 % of the roots. The intensive, small-diameter light source revealed microcracks that could not be detected when using the microscope's light alone. CONCLUSIONS: Within the limitations of this study, it could be concluded that mechanized root canal instrumentation with the ProTaper and WaveOne systems in maxillary first premolars causes microcracks in the radicular dentin, while the use of the SAF file causes no such microcracks. CLINICAL RELEVANCE: Rotary and reciprocating files with large tapers may cause microcracks in the radicular dentin of maxillary first premolars. Less aggressive methods should be considered for these teeth.

Horizontal root fractures in posterior teeth without dental trauma: tooth/root distribution and clinical characteristics.

AIM: To describe the clinical characteristics and radiographic findings of horizontal root fractures (HRF) in posterior teeth without a history of dental trauma. METHODOLOGY: A total 24 patients and 31 HRF cases in 28 posterior teeth were collected from 2006 to 2015. Clinical examinations and radiographic imaging were evaluated. Value of confidence intervals of the proportions was calculated for data presentation. RESULTS: The number of males (54%) was similar to females (46%). The patients were predominantly between 50 and 70 years of age (75%). Most HRF cases were found in nonendodontically treated teeth (79%), without crown and bridge restorations (82%), and maxillary molars (54%). Many roots of maxillary molars had developed HRF, and the probability was nearly equal. Fractured teeth usually presented with periodontal and apical bone loss, and most patients (92%) were diagnosed with full mouth chronic periodontitis. Tooth wear was another common clinical feature amongst these patients. CONCLUSIONS: HRF in posterior teeth without dental trauma occurred mainly in patients aged between 50 and 70, in nonendodontically treated teeth, teeth with attrition but without crown and bridge restorations, maxillary molars and with periodontal and periapical bony destruction. Periodontal condition, occlusal wear and patients' age at diagnosis were the possible related factors. HRF in posterior teeth without dental trauma is a diagnostic challenge and even misdiagnosed. A thorough clinical examination, radiographic analysis and recognition of the clinical characteristics are helpful in the early diagnosis and treatment of HRF.

Detection of vertical root fractures in intact and endodontically treated premolar teeth by designing a probabilistic neural network: an ex vivo study.

OBJECTIVES: Detection of vertical root fractures (VRFs) in their initial stages is a crucial issue, which prevents the propagation of injury to the adjacent supporting structures. Designing a suitable neural network-based model could be a useful method to diagnose the VRFs. The aim of this study was to design a probabilistic neural network (PNN) to diagnose the VRFs in intact and endodontically treated teeth of periapical and CBCT radiographs. Also, we have compared the efficacy of these two imaging techniques in the detection of VRFs. METHODS: A total of 240 radiographs of teeth (120 radiographs of teeth with no VRFs and 120 teeth with vertical fractures, with half of the teeth in each category treated endodontically and the remaining half intact, i.e. not endodontically treated) were used in 3 groups for training and testing of the neural network as follows: Group 1, 180/60; Group 2, 120/120; and Group 3, 60/180. First, Daubechies 3 wavelet was applied to acquire the image analysis coefficients on two planes; then Gabor filters were used to extract the image characteristics, which were used to educate the PNN. The designed neural network was able to diagnose and classify teeth with and without VRFs. In addition, in order to determine the best training and test sets in the network, the variance of the function of network changes was manipulated at a range of 0-1 and the results were assessed in terms of the parameters evaluated, including sensitivity, specificity and accuracy. RESULTS: In the periapical radiographs, the maximum accuracy, sensitivity and specificity values in the three groups were 70.00, 97.78 and 67.7%, respectively. These values in the CBCT images were 96.6, 93.3 and 100%, respectively, at the variance change range of 0.1-0.65. CONCLUSIONS: The designed neural network can be used as a proper model for the diagnosis of VRFs on CBCT images of endodontically treated and intact teeth; in this context, CBCT images are more effective than similar periapical radiographs. Limitations of this study are the use of sound one-rooted premolar teeth without carious lesions and dental fillings and not simulating the adjacent anatomic structures. Further in vitro work using a full-skull simulation for CBCT and skin/bone simulation is needed.

Effects of Stem Cell Factor on Cell Homing During Functional Pulp Regeneration in Human Immature Teeth.

Conventional root canal treatment in immature permanent teeth can lead to early tooth loss in children because root formation is discontinued. We investigated whether the stem cell factor (SCF) could facilitate cell homing in the pulpless immature root canal and promote regeneration of a functional pulp. In vitro, human mesenchymal stem cells (hMSCs) were exposed to SCF at various concentrations for assessing cell migration, proliferation, and differentiation toward odonto/osteoblasts by 3D-chemotaxis slides, WST-1 assay, and alkaline phosphatase activity, respectively. Fibrin gels were used to deliver 15 µg/mL SCF for in vivo experiments. The release kinetic of SCF was assessed in vitro. Two corresponding human immature premolars, with or without SCF, were placed at rat calvariae for 6 and 12 weeks. All tooth specimens were either analyzed histologically and the percentage of tissue ingrowth determined or the cells were extracted from the pulp space, and the mRNA level of DMP1, DSPP, Col1, NGF, and VEGF were assessed by quantitative polymerase chain reaction. In the presence of SCF, we saw an increase in hMSCs directional migration, proliferation, and odonto/osteogenic differentiation. SCF also increased the extent of tissue ingrowth at 6 weeks but not at 12 weeks. However, at this time point, the formed tissue appeared more mature in samples with SCF. In terms of gene transcription, DMP1, Col1, and VEGF were the significantly upregulated genes, while DSPP and NGF were not affected. Our results suggest that SCF can accelerate cell homing and the maturation of the pulp-dentin complex in human immature teeth.

Angled Screw Channel: An Alternative to Cemented Single-Implant Restorations--Three Clinical Examples.

This article presents three cases of single labially tilted implants restored with screw-retained single crowns. Individualized abutments with an angled screw channel were used to avoid an unesthetic vestibular access channel. This individualized abutment allows the dentist and dental technician to use the screw-retained restorations where a cemented reconstruction would otherwise have been needed.

Decision Making for Retention of Endodontically Treated Posterior Cracked Teeth: A 5-year Follow-up Study.

INTRODUCTION: The study aimed to investigate the 5-year survival of root-filled posterior cracked teeth and its related factors. METHODS: Two hundred patients who had root canal-treated posterior cracked teeth at the National Dental Centre were recalled for a 5-year review. Eighty-four patients who met the inclusion criteria were included in this study. The cases were managed following the treatment protocol for cracked teeth at the center. The data for analyses were obtained from the patients' clinical records. Statistical analyses were performed using SPSS 21.0 (SPSS Inc, Chicago, IL). The outcome measure was the presence of tooth at the time of the review. RESULTS: At 5 years, 77 teeth "survived" (92%), and 7 teeth (8 %) were extracted. Patient demographics, tooth type and location, existing restoration, number and location of cracks, presence of pretreatment signs and symptoms, and initial pulpal and periapical diagnosis did not significantly affect the survival of the teeth. Univariate analysis showed that teeth with extension of the cracks onto the pulpal floor were more often extracted (odds ratio = 4.5, P = .07). Multivariable analyses found that extension of cracks onto the pulpal floor independently increased the odds of tooth loss by 11-fold (odds ratio = 11, P = .033), with other factors being held constant. The 5-year survival estimate in the absence and presence of crack extension onto the pulpal floor was 99% and 88%, respectively. CONCLUSIONS: Coronal cracks may be predictably treated, whereas radicular cracks increased the odds of the tooth being extracted.

Fractura radicular vertical / Vertical root fracture

El propósito de este reporte es presentar el caso de un paciente femenino con presencia de fractura radicular vertical (FRV) de un segundopremolar superior izquierdo, remitida a la clínica de Postgrado de Endodonciade la Universidad De La Salle Bajío para remoción de poste y retratamiento dental. Una vez realizado el diagnóstico se determinó FRV mediante sondeo minucioso irregular en un solo punto con sonda flexible, ligero dolor a la masticación y pérdida ósea radiográfica en forma de halo o gota, se sugirió como tratamiento extracción dental y cirugía exploratoria a petición del paciente

The aim of this report is to present the case of a female patient with a vertical root fracture (VRF) of a maxillary second premolar who was referred to the Postgraduate Endodontic Clinic of De La Salle Bajío University in León, Guanajuato, Mexico for the removal of a metallic post and retreatment of root canals. Examination via thorough irregular periodontal probing at a single point with a fl exible probe resulted in a diagnosis of VRF, slight pain on chewing, and radiographic bone loss in the shape of a halo or droplet, for which the suggested treatment was the extraction of the tooth, a surgical procedure that was subsequently performed at the patient’s request.

An Evaluation of Apical Cracks in Teeth Undergoing Orthograde Root Canal Instrumentation.

INTRODUCTION: Dentinal damage and cracks induced by orthograde preparation methods have been reported in studies using extracted teeth. The purpose of this in situ investigation was to evaluate dentinal cracks in nonextracted teeth after final instrumentation. The null hypothesis is that orthograde root canal instrumentation will have no effect on crack initiation in teeth retained in the natural periodontium. METHODS: Mandibular first and second premolars of pig jaws were selected. Forty single-rooted canals were divided into 5 groups (n = 8): (1) WaveOne (Dentsply Tulsa Dental Specialties, Tulsa, OK) 25/08; (2) ProTaper rotary S1, S2, F2 (25/08) (Dentsply Tulsa Dental Specialties); (3) crown-down GT hand files 20/12, 20/10, 20/08 (Dentsply Tulsa Dental Specialties); (4) positive control (purposefully cracked); and (5) negative control (uninstrumented teeth). After instrumentation, superficial soft tissue was removed, and bone was carefully peeled away with surgical burs to the level of the root apices. Roots were resected 1 mm coronal to the working length, stained with caries indicator dye, and transilluminated; images were captured and viewed at 30× magnification to determine the presence or absence of dentinal cracks. RESULTS: WaveOne, ProTaper rotary, and GT hand files produced no cracks. All positive controls had cracks; all negative controls had no cracks. CONCLUSIONS: Within the limits of this investigation, the presence of natural periodontal structures may prevent cracking or dentinal damage in teeth receiving orthograde root canal instrumentation.

In vivo Evaluation of Proximal Resin Composite Restorations performed using Three Different Matrix Systems.

OBJECTIVE: The aim of this in vivo study was to radiographically evaluate the proximal contour of composite resin restorations performed using different matrix systems. MATERIALS AND METHODS: Patients with premolars needing class II type resin composite restorations involving the marginal ridge were selected. Thirty premolars were selected and randomly divided into three groups (n = 10 each) to receive restorations using different matrix systems: group 1: metal matrix coupled to a carrier matrix and wood wedge (G1-MMW); group 2: sectioned and precontoured metal matrix and elastic wedge (G2-SME); and group 3: a polyester strip and reflective wedge (G3-PMR). After the restorative procedure, bitewing radiographs were performed and analyzed by three calibrated professionals. The quality of the proximal contact and marginal adaptation of the proximal surfaces was classified as either correct or incorrect (undercontour/overcontour). RESULTS: The Pearson Chi-square statistical test (α = 5%) revealed a statistically difference between frequencies of correct and incorrect restorations (α(2) = 6.787, p < 0.05). The group G2 SME produced a higher frequency of correct proximal contours (90%), while G1-MMW and G3-PMR had a ratio of 40% correct and 60% incorrect contours respectively. CONCLUSION: None of the matrix systems was able to prevent the formation of incorrect proximal contours; however, the sectioned and precontoured metal matrix/elastic wedge configuration provided better results as compared to the other groups.